Service providers typically provide numerous voice and data services to end users (also referred to as subscribers). Examples of voice services are voice calls, call forwarding, call waiting, etc. Examples of data services are streaming audio, streaming video, Voice over Internet Protocol (VoIP), online gaming, and IP-TV. The data services are managed by a packet core network, which interfaces the end user with external packet data networks (PDN), such as the Internet. Some examples of packet core networks are a General Packet Radio Service (GPRS) core network, an Evolved Packet Core (EPC) network, etc. To utilize data services, an end user uses a mobile device, such as a cell phone, to connect with a Radio Access Network (RAN). The RAN may be a packet-based network that provides IP connectivity, which is also referred to as an IP Connectivity Access Network (CAN). The RAN in turn connects to the packet core network in order to provide the end user with access to the data services.
When the mobile device initiates a session (e.g., an IP-CAN session), the session request from the mobile device includes a description of the requested service (e.g., online gaming, IP-TV, etc). The packet core network authenticates the mobile device and determines which services the mobile device is authorized to receive. If the requested service is authorized, then the packet core network reserves a bearer path (e.g., an IP CAN bearer) of a defined capacity, delay, and bit error rate over a selected Packet Data Network (PDN). A flow of packets may then begin for the service, which is referred to as a service data flow over the PDN.
Network operators implement Policy and Charging Control (PCC) within their networks to control how services are provided to end users. Policy control refers to the process of controlling the bearer path for service data flows, such as for bearer establishment, Quality of Service (QoS) control, and gating control (blocking or allowing packets to pass). Policy rules are predefined for each end user and govern which network services the end user is allowed to access, the bandwidth level that is provided, when the services are allowed, how long the services are allowed, etc. Charging control refers to the process of associating packets of a service data flow with a charging key or charging identifier, and applying online charging and/or offline charging as appropriate. Charging rules are predefined for each end user and govern the type of charging applied to a service, the tariff(s) applied to a service, etc. The policy rules and charging rules are set out in a service plan subscribed to by the end user.
The 3rd Generation Partnership Project (3GPP, 3GPP2) has defined a PCC architecture that provides policy and charging control for packet core networks. One example of a PCC architecture is described in 3GPP TS 23.203 (Release 9). The PCC architecture suggested by the 3GPP includes a Policy and Charging Rules Function (PCRF), a PDN gateway comprising a Policy and Charging Enforcement Function (PCEF), an application function (AF), a Bearer Binding and Event Reporting Function (BBERF), a Home Subscriber Server (HSS)/Subscription Profile Repository (SPR), an Online Charging System (OCS), and an Offline Charging System (OFCS). As a brief description of some of the elements of the PCC architecture, the PCRF makes policy control decisions and flow-based charging control decisions to select which PCC rules to implement for a service data flow. The PCEF in the gateway provides service data flow detection, user plane traffic handling, QoS handling, service data flow measurement, and online/offline charging interactions. The HSS/SPR stores subscriber data and subscription related information for end users, such as in subscriber profiles.
The PCRF in the PCC architecture makes a PCC decision when an end user requests a service. Presently, the PCRF makes the PCC decision based on a predefined set of policy rules and charging rules for the end user that are set out in his/her service plan. For example, an end user may subscribe to a “gold” class of service that guarantees 10 Mbps of download speed and 2 Mbps of upload speed. The network operator can guarantee these download and upload speeds most of the time. But, there are instances where these speeds may not be possible, such as when there is congestion in an area of the RAN. Network operators continue to look for ways to handle congestion issues within the network, such as in the RAN.